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SubjectRe: [PATCHv3 1/2] i2c: designware: introduce a custom scl recovery for SoCFPGA platforms
On Mon, Jun 13, 2022 at 04:00:31PM -0500, Dinh Nguyen wrote:
> The I2C pins on the SoCFPGA platforms do not go through a GPIO module,
> thus cannot be recovered by the default method of by doing a GPIO access.
> Only a reset of the I2C IP block can a recovery be successful.
>
> The assignment of the recover_bus needs to get done before the call to
> devm_gpiod_get_optional(), otherwise, the assignment is not taking place
> because of an error after returning from devm_gpiod_get_optional().

Thanks for an update!
My comments below.

...

> +static int i2c_socfpga_scl_recovery(struct i2c_adapter *adap)
> +{
> + i2c_dw_prepare_recovery(adap);
> + i2c_dw_unprepare_recovery(adap);

Can we use

struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;

bri->prepare_recovery(adap);
bri->unprepare_recovery(adap);

> + return 0;
> +}

instead and...

...

> static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
> {
> struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
> struct i2c_adapter *adap = &dev->adapter;
> struct gpio_desc *gpio;
>
> + if ((dev->flags & MODEL_MASK) == MODEL_SOCFPGA) {
> + rinfo->recover_bus = i2c_socfpga_scl_recovery;
> + adap->bus_recovery_info = rinfo;
> + }
> +
> gpio = devm_gpiod_get_optional(dev->dev, "scl", GPIOD_OUT_HIGH);
> if (IS_ERR_OR_NULL(gpio))
> return PTR_ERR_OR_ZERO(gpio);

...this one to be transformed like (in a preparatory patch and in this one):

static int i2c_dw_init_socfpga_recovery_info(struct dw_i2c_dev *dev,
struct i2c_bus_recovery_info *rinfo)
{
rinfo->recover_bus = i2c_socfpga_scl_recovery;
return 0;
}

static int i2c_dw_init_generic_recovery_info(struct dw_i2c_dev *dev,
struct i2c_bus_recovery_info *rinfo)
{
struct i2c_adapter *adap = &dev->adapter;
struct gpio_desc *gpio;

gpio = devm_gpiod_get_optional(dev->dev, "scl", GPIOD_OUT_HIGH);
if (IS_ERR_OR_NULL(gpio))
return PTR_ERR_OR_ZERO(gpio);

rinfo->scl_gpiod = gpio;

gpio = devm_gpiod_get_optional(dev->dev, "sda", GPIOD_IN);
if (IS_ERR(gpio))
return PTR_ERR(gpio);
rinfo->sda_gpiod = gpio;

rinfo->recover_bus = i2c_generic_scl_recovery;

dev_info(dev->dev, "running with gpio recovery mode! scl%s",
rinfo->sda_gpiod ? ",sda" : "");

return 0;
}

static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
{
struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
struct i2c_adapter *adap = &dev->adapter;
int ret;

switch (dev->flags & MODEL_MASK) {
case MODEL_SOCFPGA:
ret = i2c_dw_init_socfpga_recovery_info(dev, rinfo);
break;
default:
ret = i2c_dw_init_generic_recovery_info(dev, rinfo);
break;
}
if (ret)
return ret;

rinfo->prepare_recovery = i2c_dw_prepare_recovery;
rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;
adap->bus_recovery_info = rinfo;

return 0;
}

--
With Best Regards,
Andy Shevchenko


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